textproduct: Quad Cities

KEY MESSAGES

- Freezing rain possible during evening commute today, especially across northwest Illinois and extreme eastern Iowa mainly along/north of Hwy 30.

- Vigorous snow showers and the possibility of snow squalls will accompany a strong cold frontal passage overnight/early Wednesday morning.

- Windy conditions tonight/Wednesday with peak gusts possibly 45-50+ mph timed for a several hour period after a cold front moves through.

- Additional clipper systems will likely result in periods of accumulating snow Thursday through Sunday.

- Temperatures will drop for the weekend with wind chills well below zero Friday and Saturday night.

SHORT TERM /THROUGH WEDNESDAY/

Issued at 341 AM CST Tue Dec 9 2025

Initial clipper system and attendant WAA wing of light snow has moved off to the east early this morning. Lingering low stratus extends across parts of NE Iowa and N Illinois and monitoring for any freezing drizzle potential in continued WAA. However, saturation depth is in question and higher ceilings generally show to where this potential seems very low, but non-zero at this time.

Meanwhile, upstream the next clipper system is diving southeast toward the Northern Plains early this morning. This system will deepen as it dives through the Upper Midwest tonight/early Wednesday with ensemble and deterministic guidance in decent agreement on a sub 990 mb surface low tracking from MN through WI. There remains continued uncertainty with how warm temps will get today given the snow cover and cloud cover, particularly across the north. Have continued to follow toward cooler raw models for highs today versus warmer NBM, especially across the northern counties. Thus, have temps only into the lower 30s there, but low to mid 40s far south. WAA wing of precipitation is anticipated to push through the cwa late today through this evening, with soundings generally supportive of limited ice to where the bulk of the precipitation is expected to fall in the form of rain. Surface temps will be critical for freezing rain potential, and with the freezing line anticipated to be in our north this would support areas near/north of Hwy 30 with the best chance for a transient period of freezing rain leading to potential for some slippery travel for the evening commute. Thus, have opted for a Winter Weather Advisory for much of the area north of Hwy 30.

Ahead of the clipper this evening we'll see south winds turn more westerly and turn gusty with gusts over 30+ mph and temperatures continuing to warm ahead of an attendant cold front, thus the freezing rain potential looks to be rather fleeting at only a couple hours at any one location across our northern counties.

Overnight into Wednesday morning we'll see a strong cold front sweep across the area. Some of the hi-res guidance is supporting the potential for some robust snow showers and possibly snow squalls accompanying the front given some weak surface based instability and saturation coupled with with lapse rates reaching well into the DGZ. Momentum transfer supports potential for some gusty winds possibly over 40-45+ mph leading to sharply reduced visibilities and possibly a quick minor coating of snow. After the front and snow showers sweep through, the signal remains for at least advisory criteria winds through the morning on Wednesday with strong CAA and impressive 50+ kt winds at 850 mb along with a unidirectional profile and steep lapse rate environment. Question is what's the best approach for a headline given the complex nature of the setup between transient short period of impactful snow showers/squalls, and concerns for ground blizzard - mainly with neighbors north/west. In terms of the ground blizzard the feeling is age of recent added snow (3 days) coupled with warming at or above freezing all locations briefly this evening/tonight and also some light rain/freezing rain may work in tandem to limit this potential in our region. Bottom line, since we've still got some time wanted to allow for that to continue to assess and nail down the risk and appropriate headline(s).

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/

Issued at 341 AM CST Tue Dec 9 2025

The pattern looks to remain active throughout the period with clipper systems bringing precip chances about every couple of days or so. With that, the deterministic models and ensembles are starting to converge on the next clipper and snow chance arriving by Thursday night. Amounts look to be light with this system. Arctic air will follow by the weekend. There is a signal for a stronger clipper system potentially on Saturday, which combined with colder SLRs in the arctic airmass may result in the potential for several inches of accumulation for parts of the area. Blustery winds will also accompany the arctic air and could result in wind chills potentially nearing -25F at times across our northern counties over the weekend.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 550 AM CST Tue Dec 9 2025

Stratus with lower MVFR to IFR ceilings is lurking just north of the DBQ terminal at the start of the period. To the south some areas of fog and IFR/MVFR visibilities were noted near CID. Between the fog and potential for additional stratus/stratocu development I've opted for an IFR/MVFR period at both sites this morning before going to VFR. Certainly a challenging forecast particularly for DBQ as there's also some potential to remain with degraded conditions all day in low clouds/fog with brief bout of subsidence. Otherwise, predominantly VFR expected today at MLI and BRL. Winds today will be from south/southwest and should turn gusty 15-25 kt by late in the day.

This evening, strong elevated warm/moist advection on 50-60+ kt LLJ should foster a transitory wing of light precipitation. Expect this to be rain/sprinkles at MLI and BRL. CID and especially DBQ may be close to freezing for possibly a brief period of light freezing rain before going over to rain as temps further warm this evening. Any icing would be a very light glaze. The freezing rain threat will be determined by how surface temperatures trend, and so this potential will continue to be refined in later forecasts.

After 06z through 12z, a strong cold front will sweep through the area. Ahead of this front, LLWS will be a threat with westerly winds around 50-55 kts near 2kft agl, while surface winds will be gusty from S/SW at 15-25+ kts. Scattered snow showers will also accompany the cold front along with increased surface wind gusts from W/NW at 30-40+ kts. This may lead to brief periods of signficant visibility reduction. For now this potential has been handled with PROB30 mention late in the period.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Winter Weather Advisory from 6 PM this evening to midnight CST tonight for IAZ040>042-051>054. IL...Winter Weather Advisory from 6 PM this evening to midnight CST tonight for ILZ001-002-007. MO...None.